Day: March 12, 2014

If you’re like us, you probably have a box (or more) of wall warts lurking in a closet or on a shelf somewhere. Depending on how long you’ve been collecting cell phones, that box is likely overflowing with 5V chargers: all with different connectors. Bring them back to life by doing what [Martin Melchior] did: chop off the ends and solder on a bunch of USB jacks.

You’ll want to use chargers rated for at least 500mA (if not 1A) for this project, or you may be wasting your time considering how much current devices pull these days. Get your polarity right, solder on a USB jack, and you’re finished. Sure, it’s a no-brainer kind of project, but it can clean out some of your closet and give you a charging station for every room of your home and the office. [Martin] glued the USB jack directly onto the adapters, so there are no tangled cords to worry about. iPhone users will need to do the usual kungfu if you want your Apple device to charge.

[Jonas] over at LOM Instruments is running an Indiegogo campaign for his newest creation, Elektrosluch 2. Like it’s predecessor, Elektrosluch 2 is a means to listen to the electromagnetic sounds of the world around you. Fans, computers, cell phones, routers, and just about anything electronic create strange and interesting sounds when probed with Elektrosluch 2. The campaign seems to be doing well enough with its target audience of experimental music and audio folks. However at €45 ($62.37) it’s a bit pricey for our blood. Unfortunately, [Jonas] hasn’t open sourced the project. All hope is not lost though, as Elektrosluch 2 appears to be simple enough that our astute readers should be able to build their own.

The concept is easy to understand: a coil of wire placed within a magnetic field will have an induced current proportional to the strength of the field. Electric Guitar pickups operate on the same basic principles. [Jonas] appears to be using two coils – probably tuned to different frequencies. We’re talking about relatively small magnetic fields here, so the signal will need to be amplified. In the Elektrosluch 2, the amplifier is an 8 pin SOIC which we can’t quite make the label out on. A few capacitors and resistors limit the bandwidth to audio frequencies.

[Alan Yates] created a similar circuit to diagnose dead Christmas lights. In [Alan’s] case, he used a pin instead of a coil. Two transistors and a handful of discrete components performed the amplification duties.

Has it really been three months since our last Staff Update? Even though you’ve been enjoying posts from these guys for quite some time now a proper introduction is in order. From left to right, please join me in welcoming [Bil Herd], [Rich Bremer], [Nick Conn], and [Abe Connelly] to the team.

[Bil] started out with a guest post on the C128 which I absolutely loved. We got to talking and he mentioned an interest in putting out some video content. His first offering for Hackaday was the segment on calculating component heat. He has a few more in the pipeline and I’m sure he’d love to hear your ideas for the subjects of future videos.

I like to choose contributors who have a wide range of interests: [Rich] has a mechanical engineering background. Nick, who is working on his Ph.D., has quite a bit of experience with medical devices. This is not to be confused with the type of bio-medical hacking which [Abe] is interested in. Learn more about all of their backgrounds over on the Hackaday Staff page.

All of the people who have joined us over the last six months came form a pool of applications received after a September hiring announcement. I posted another one last week and have received numerous applications. I’m still reviewing them so don’t worry if you haven’t heard from me, you will soon!

Here’s another one of those crazy, weird, artsy-style hacks. Somebody decided to see what tree rings sound like by making this rather unorthodox turntable.

All things considered, the cross-section of a tree trunk does kind of resemble a vinyl record. [Bartholomäus Traubeck] noticed this and decided to see what would happen if you could listen to it.

Of course… it’s not quite that simple. When you cut a slice of wood, you’re not leaving any grooves in the rings, so you can’t just throw it on a slightly modified record player. What [Traubeck] had to do was engineer a record player with a Playstation Eye camera strapped to the end of the arm — simple image recognition software creates a signal based on the pattern of the rings, knots, and other imperfections in the wood. This is then filtered into a program called Albeton Live, and converted into a very angst-y piano track.

The Hackaday community is currently very busy coding the low-level libraries of our open-source offline password keeper project. And when many talented contributors work together on a common concept, interesting discussions take place. In our dedicated Google Groups, some of them were about the choice of naming/coding conventions and also how/when to approve GitHub pull requests. But don’t leave already… this topic is actually more interesting than it sounds.

The age difference between the older and younger firmware contributor is guessed to be approximately 30 years… and many things can happen in such a time frame. Even though our coders are writing in C, most of them code in other programming languages at school/work. They also use different text editors on different operating systems. Understandably, each one of them therefore has its preferred coding / naming convention and indent style. The Mooltipass conventions were selected based on majority voting, and after many emails we settled on an Allman style convention with camelCase:

main(void)

{

if (foo)

{

functionCall();

}

else

{

foo = 0;

anotherFunctionCall();

}

}

- 79 characters line length as a soft requirement

- 4 spaces, no tabs

Most of the contributors believe that it is the best compromise between code clarity and cross-platform compatibility, but we would be curious to know our Hackaday readers’ opinions on this particular topic.

The second matter is a bit more of a management one. What is the best strategy to manage and review code changes made to a main GitHub repository, when a project is at its infancy and composed of (more or less) non-remunerated contributors?
It is perfectly understandable that interest, spare time and willingness to contribute may vary over time. Perhaps some of our readers may already be familiar with Agile software development, a group of software development methods based on iterative and incremental development, which promotes adaptive planning, evolutionary development and encourages rapid and flexible response to change. Do you think this can be applied to the Mooltipass project?

We would be curious to hear similar experiences on these topics, as we gladly accept constructive criticism. You may also want to join our dedicated Google group to check out the different discussions that already happened there. On a side note, we are also currently looking for capacitive wheel / touch button footprints libraries for Kicad.

Hackaday happened to be at South by Southwest this year and visited SXSW Create – part of the festival dedicated to hackers, makers and DIY scene. While modest in size, this event serves as a great contrast to the internet-hype machine omnipresent everywhere else in the city during this time. So we thought we should drop by and show them some love.

Trey German showed us a couple of great real-time power control demos using his C2000 Launch Pad as well as his Bluetooth Cooler which, for whatever reason, decided to fail on him just in time for the big show. The demo we have been looking forward to the most was a thermocouple-controlled barbecue using Energia framework but were disappointed to learn that The Man has banned grilling hotdogs in the tent. The universe was telling us we’re not here to party.

ATX Hackerspace had a large booth featuring the full-size replica of Doctor Who’s TARDIS (who wouldn’t like to have a picture taken in one ?) and a fully-functional 1930-es vacuum tube radio with a mandatory iPad dock. We have also learned that a massive collection of working vintage vacuum tubes has been donated to the hackerspace, so if you’re in need you know who to call.

The event has also featured a long list of industry participants. The product launch we were most impressed with was Easel by Inventables, an in-browser app that enables easy control of their Shapeoko CNC milling machine and definitely has the potential of bringing the joys of design and fabrication to much larger masses.

However, the most interesting things we saw were the ones a bit outside of the current tech mainstream. [Dennis] from UT Austin iGEM team showed some of the crazy work the synthetic biologists are doing out there. They have engineered Escherichia coli so that it is addicted to caffeine, used cell growth as a measure of caffeine content in particular drinks, and used that to rank local Austin coffee shops! We have also talked with several guys working on automated gardens and soil sensors who were educating attendees about the huge potential that increased environmental data aggregation can have on the ways we grow food.

They say necessity is the mother of invention. Sometimes the necessity is simply avoidance of unpleasant tasks such as cutting down 3500 header pins by hand. [Nixieguy] and his coworkers were faced with 50 prototype boards bearing 70 overly long pins apiece. He saved them from cutting them all down by hand by making a tiny improvised circular saw/grinder.

[Nixieguy] started by laser-cutting a combination tool holder and grinding platform. His laser failed before he could fashion a guard to keep the pin bits out of the motor or cut all the pieces he had in mind. The grinder is made from a 10A brushless RC motor, a motor driver, and a servo tester. [Nixieguy] machined an adapter to connect the disc to the shaft.

The transformer is there to hold the thing down during use since it’s so lightweight. He’s wearing two pairs of gloves because the pin cuttings were hot enough to sear skin. [Nixieguy] is planning on a complete redesign including a motor guard and the ability to adjust the depth. Maybe he can turn it into a chainsaw, maybe not.